Electric variable-air-volume diffuser

ABSTRACT

A variable-air-volume (VAV) diffuser includes a diffuser housing that is formed for coupling to a supply air conduit. The diffuser housing defines a discharging opening for discharge of supply air from the supply air conduit into a room. The VAV diffuser may also include a supporting structure that is affixed to the diffuser housing, and a flow controller for varying the volume of supply air discharged through the discharging opening. The VAV diffuser may further include an electric actuator that is mounted on the supporting structure for moving the flow controller to vary the volume of supply air. The electric actuator may be accessible from room side and removable from the diffuser housing while the diffuser housing is coupled to the supply air conduit, the supporting structure is affixed to the diffuser housing and the flow controller remains within the diffuser housing.

FIELD OF INVENTION

The present invention generally relates to a variable-air-volume diffuser for regulating air flow, and more specifically to a variable-air-volume diffuser powered by an electric motor for varying the volume of supply air to a space.

DESCRIPTION OF RELATED ART

Variable-air-volume (VAV) diffusers are used in various applications. One of the most common uses is in heating, ventilating and air conditioning (HVAC) system to deliver supply air to a space that needs to be conditioned. In response to a thermal load, which depends on many factors and varies considerably from time to time and from space to space, the VAV diffusers adjust the volume of supply air discharged to the selected space to achieve the desired conditioning effect.

An exemplar of regulating the volume flow of conditioned air can be found in U.S. Pat. No. 6,176,777 to Smith et al., which discloses a self-modulating diffuser for air conditioning systems. Another exemplar is U.S. Pat. No. 5,860,592 to Dozier et al., which discloses a VAV diffuser with independent ventilation air assembly and method. Other exemplars of air diffusers or VAV air diffusers can be found in U.S. Patent Application Publication No. 2006/0292977 to Caldwell et al. which discloses electrically powered air diffusers, in U.S. Pat. No. 6,997,799 to Mrozek et al. which discloses a damper including a stepper motor, and in U.S. Pat. No. 6,224,481 to McCabe which discloses electric power modulated lead screw actuated butterfly blade damper.

Although current VAV diffusers can adjust the volume of supply air, they may be at a disadvantage in terms of maintenance serviceability and/or energy efficiency and/or condensation management. In order to access the interior for a maintenance service, current VAV diffusers typically need to be dismounted or disassembled from the HVAC system. For instance, to repair or replace an actuator or a motor, current VAV diffusers may require dismounting the entire VAV diffusers from the HVAC system or disassembling majority of components from the VAV diffusers. This process increases downtime and maintenance cost. In addition, current VAV diffusers cannot be used for discharging supply air at lower temperatures without the formation of condensation.

In light of the above, it is desirable to provide improved pressure control valves or assemblies that overcome at least some of the above-mentioned challenges.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY

Various aspects of the present application are directed to provide a variable-air-volume (VAV) diffuser that provides a number of advantages including easy serviceability, energy efficiency and/or condensation management.

One aspect of the present application is directed to provide a VAV diffuser including a variable-air-volume diffuser including a diffuser housing formed for coupling to a supply air conduit and defining a discharging opening for discharge of supply air from the supply air conduit into a room, a supporting structure affixed to the diffuser housing, a flow controller for varying a volume of supply air discharged through the discharging opening, and an electric actuator mounted on the supporting structure for moving the flow controller to vary the volume of supply air, wherein the electric actuator is room-side accessible and removable from the diffuser housing while the diffuser housing is coupled to the supply air conduit, the supporting structure is affixed to the diffuser housing and the flow controller remains within the diffuser housing.

The flow controller may be movably mounted on the supporting structure. The flow controller may be pivotally mounted on the supporting structure by a hinge. The flow controller may include a plurality of blades and each blade may be movably mounted on the supporting structure. The flow controller may include four blades and each of the four blades may be movably mounted on the supporting structure.

The electric actuator may include a stepper motor. The electric actuator may be removably mounted on a bracket that is affixed on the supporting structure.

The variable-air-volume diffuser may further include a linkage assembly that connects the flow controller to the electric actuator, wherein the linkage assembly may be configured such that the electric actuator rotates the flow controller around the hinge. The variable-air-volume diffuser may further include a plurality of linkage assemblies, each linkage assembly connecting a respective blade of the plurality of blades to the electric actuator.

The supporting structure may be formed with a shaft hole and a linkage hole. The electric motor may include a threaded shaft that extends substantially upwardly through the shaft hole in the supporting structure. The linkage assembly may include a hub threadedly coupled to the threaded shaft of the electric actuator, a first link affixed to the hub at one end and extending downwardly through the linkage hole in the supporting structure, a second link rotatably mounted on the supporting structure at one end, a third link rotatably mounted on the flow controller at one end, and a fourth link, one end of the fourth link rotatably connected to the other end of the first link and the other end of the fourth link rotatably connected to the other ends of the second and third links. The hub may be operably coupled to the threaded shaft of the electric actuator. The supporting structure may be formed with a mounting hole for mounting and removing the electric actuator.

The variable-air-volume diffuser may further include a guide affixed to the supporting structure and extending substantially upwardly for preventing rotation of the flow controller.

The electric actuator may include a threaded shaft that extends substantially upwardly, and the flow controller may be formed with a shaft hole and a guide hole, wherein the flow controller may be threadedly coupled with the threaded shaft of the electric actuator through the shaft hole and may be slidably coupled with the guide through the guide hole.

The flow controller may be a disk.

The variable-air-volume diffuser may further include an appearance plate that may be removably attached to the supporting structure. One edge of the appearance plate may be rotatably hinged to a bracket affixed on the supporting structure, and the opposite edge of the appearance plate may be detachably secured to the supporting structure.

The variable-air-volume diffuser may further include an insulation layer that may be overlaid at least on a portion of the flow controller.

The variable-air-volume diffuser may further include a sensor for measuring room temperature, temperature of the supply air, or flow rate of the supply air.

The diffuser housing may include a diffuser neck formed for coupling to the supply air conduit, and a diffuser cone formed for discharging the supply air in an angle with respect to a downward direction, wherein the diffuser neck and the diffuser cone may be integrally formed or coupled to each other.

Another aspect of the present invention is directed to a variable-air-volume diffuser including a diffuser housing formed for coupling to a supply air conduit and defining a discharging opening for discharge of supply air from the supply air conduit into a room, a supporting structure affixed to the diffuser housing, a plurality of blades movably mounted on the supporting structure for varying a volume of supply air discharged through the discharging opening, and a linkage assembly connecting the plurality of blades to an electric actuator, wherein the electric actuator is accessible from room side and removable from the diffuser housing while the diffuser housing is coupled to the supply air conduit and the supporting structure is affixed to the diffuser housing and connected to the linkage assembly.

Still another aspect of the present invention is directed to a variable-air-volume diffuser including a diffuser housing formed for coupling to a supply air conduit and defining a discharging opening for discharge of supply air from the supply air conduit into a room, a supporting structure affixed to the diffuser housing and formed with a mounting hole, a flow controller for varying a volume of supply air discharged through the discharging opening, a guide affixed to the supporting structure and extending substantially upwardly for preventing rotation of the flow controller, and an electric actuator mounted on the supporting structure through the mounting hole for moving the flow controller to vary the volume of supply air, wherein the electric actuator is room-side accessible and removable from the diffuser housing through the mounting hole of the supporting structure while the diffuser housing is coupled to the supply air conduit, the supporting structure is affixed to the diffuser housing and the flow controller remains within the diffuser housing.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like numerals describe similar components throughout the several views. Like numerals having different letter suffixes represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments disclosed herein.

FIG. 1A illustrates a cross-sectional view of an exemplary fully-opened VAV diffuser in accordance with the present application.

FIG. 1B illustrates a cross-sectional view of an exemplary partially-opened VAV diffuser in accordance with the present application.

FIG. 1C illustrates a cross-sectional view of an exemplary closed VAV diffuser in accordance with the present application.

FIG. 2A illustrates a cross-sectional view of an exemplary fully-opened alternative VAV diffuser in accordance with the present application.

FIG. 2B illustrates a cross-sectional view of an exemplary partially-opened alternative VAV diffuser in accordance with the present application.

FIG. 2C illustrates a cross-sectional view of an exemplary closed alternative VAV diffuser in accordance with the present application.

FIG. 2D illustrates an exemplary room air induction channel that may be utilized with the exemplary VAV diffuser of FIG. 2A.

FIG. 3 illustrates a prototype of an exemplary VAV diffuser with an insulation layer in accordance with the present application.

FIG. 4A illustrates a perspective view of an exemplary VAV diffuser mounted on a ceiling in accordance with the present application

FIG. 4B illustrates a perspective view of an exemplary VAV diffuser mounted on a ceiling in accordance with the present application, showing an operation to open an appearance plate.

FIG. 4C illustrates a perspective view of an exemplary VAV diffuser mounted on a ceiling in accordance with the present application, showing an operation to dismount an actuator.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

Referring to FIGS. 1A-1C, there are respectively depicted a fully opened, a partially opened and a fully closed exemplary variable-air-volume (VAV) diffuser 100. The VAV diffuser 100 can be used to regulate supply air to a selected space. For use in a commercial building, the VAV diffuser 100 is usually mounted to a ceiling. In various embodiments, the exemplary VAV diffuser 100 generally includes a diffuser housing 102 that is formed for coupling to a supply air conduit. The diffuser housing 102 defines a discharging opening for discharge of supply air from the supply air conduit into a space, such as a room, that requires heating or air-conditioning. The exemplary VAV diffuser 100 may also include a supporting structure 104 that is affixed to the diffuser housing 102 and a flow controller 106 for varying a volume of supply air discharged through the discharging opening. In various embodiments, the supporting structure 104 may serve as a diffuser plate. The exemplary VAV diffuser 100 may further include an electric actuator 108 that is removably mounted on the supporting structure 104. The electric actuator 108 provides driving force to move the flow controller 106 for varying the volume of supply air. In various embodiments, the exemplary VAV diffuser 100 is configured such that the electric actuator 108 is room-side accessible, that is accessible from the room side and removable from the diffuser housing 102 while the diffuser housing 102 is coupled to the supply air conduit, the supporting structure 104 is affixed to the diffuser housing 102 and the flow controller 106 remains within the diffuser housing 102.

The diffuser housing 102 may include a diffuser neck 110 for coupling to a respective supply air conduit and a diffuser cone 112 for discharging the supply air. The diffuser neck 110 and the diffuser cone 112 may be formed separately and then coupled together; they may also be formed monolithically or integrally, for example by die-forming a metal sheet. Instead of discharging the supply air directly downward, the diffuser cone 112 allows the discharged supply air flowing away from the VAV diffuser 100 in an angle. The supply air discharged in this manner mixes with room air before it gradually descends, thus promoting Coand{hacek over (a)} effect. The shape and size of the diffuser housing 102, the diffuser neck 110 and the diffuser cone 112 may vary in accordance with the present application. In general, the diffuser housing 102 has a centerline or a central axis A, which extends substantially vertically when the exemplary VAV diffuser 100 is mounted in a ceiling. In various embodiments, the diffuser cone 112 may have a square cross section at the opening.

As shown in FIGS. 1A-1C, the supporting structure 104 may be affixed to the diffuser housing 102 by mechanical fasteners, for example by one or more bolts 114, or rivets, and/or other suitable fastening means. The supporting structure 104 may be also affixed to the diffuser housing 102 by other suitable means, such as welding, adhesion, or other suitable means. The supporting structure 104 may be circular, polygonal or of any other suitable shape. In some cases where the supporting structure 104 is rectangular or square, four bolts 114 may be used, with one bolt positioned proximate to one corner of the rectangular or square supporting structure 104. The supporting structure 104 may be formed with a shaft hole 116 and one or more linkage holes 118. Further, the supporting structure 104 may be formed with a plurality of holes or nozzles that allows supply air to pass for inducing room air into the region. This feature and operation is indicated in FIG. 1A by the dashed arrow line.

In various embodiments, the flow controller 106 is movably mounted on the supporting structure 104. In particular, the flow controller 106 may be pivotally mounted on the supporting structure 104 by mechanical fasteners, such as by a hinge 120. The flow controller 106 may be a vane, a blade, a flap or the like. The flow controller 106 may include a plurality of vanes, blades or flap, or a combination thereof. In some cases where the supporting structure 104 is a polygon, such as a square, the flow controller 106 is preferably mounted proximity to an edge of the polygonal supporting structure 104. For example, the flow controller 106 may include four blades, and each blade is pivotally mounted proximity to one edge of a square supporting structure 104. The flow controller 106 can be controlled and moved to a fully opened position as shown in FIG. 1A and to a fully closed position as shown in FIG. 1C. The flow controller 106 can also be controlled and moved to any intermediate position, as shown in FIG. 1B, that is in between the fully opened position and the fully closed position to vary the flow or the volume of the discharged supply air.

With continuous reference to FIGS. 1A-1C, in various embodiments, the electric actuator 108 may be mounted on the supporting structure 104. Preferably, the electric actuator 108 may be mounted on the room side of the supporting structure 104 and by mechanical fasteners so that electric actuator 108 is readily accessible and easily removable. For example, the electric actuator 108 may be removably secured to a mount 122. The mount 122 may be affixed or secured, for example by welding, to the supporting structure 104 at one end. The other end of the mount 122 may be angled and have a threaded hole to receive a screw for mounting the electric actuator 108. The mount 122 may be a bracket. To stabilize the electric actuator 108 and reduce vibration, a plurality of mounts 122, for example four, may be used for mounting the electric actuator 108 to the supporting structure 104.

In various embodiments, the electric actuator 108 includes a motor 124 and a threaded shaft 126 that extends outwardly from the motor 124. The motor 124 may be a stepper motor. With a stepper motor, feedback sensors may be unnecessary because it can be commanded to move and hold at one of equally divided steps. The threaded shaft 126 may extend through the shaft hole 116 formed in the supporting structure 104 when the electric actuator 108 is mounted to the supporting structure 104. Preferably, the supporting structure 104 and the shaft hole 116 are configured such that the electric actuator 108 is positioned substantially along the centerline or the central axis A of the diffuser housing 102, and the threaded shaft 126 extends substantially upwardly through the shaft hole 116 formed in the supporting structure 104 once the VAV diffuser 100 is mounted to a ceiling. The threaded shaft 126 may be coupled with the flow controller 106 through a linkage assembly.

By way of illustration, FIGS. 1A-1C depicts an exemplary linkage assembly 128 including a hub 130. In some cases, the hub 130 may be formed with a threaded hole, which threadedly couples the hub 130 with the threaded shaft 126 of the electric actuator 108. In other cases, the hub 130 may be formed with a through hole, through which the threaded shaft 126 of the electric actuator 108 extends. In such cases, a nut 140 may be used to couple the hub 130 with the threaded shaft 126 of the electric actuator 108. The nut 140 may be affixed on the hub 130 such as by welding, or monolithically or integrally formed with the hub 130.

The exemplary linkage assembly 128 may further include a first link 132, a second link 134, a third link 136 and a fourth link 138. In various embodiments, the first link 132 may be affixed to the hub 130 at one end, such as by welding or by suitable mechanical fasteners, and extend downwardly through the linkage hole 118 formed in the supporting structure 104. The second link 134 may be rotatably mounted on the supporting structure 104 at one end and the third link 136 may be rotatably mounted on the flow controller 106 at one end. The first link 132 may be connected to the second link 134 and the third link 136 by the fourth link 138. For example, one end of the fourth link 138 may be rotatably connected to the other end of the first link 132 and the opposite end of the fourth link 138 may be rotatably connected to the other ends of the second link 134 and the third link 136. Suitable components or mechanisms for rotatably mounting the second link 134 and the third link 136 and for rotatably connecting the first link 132 with the second link 134 and the third link 136 may include hinges, bearings, pins, rivets or brackets.

One would appreciate that the configuration of the exemplary linkage assembly 128 depicted in FIGS. 1A-1C is illustrative only and is not intended to be in any way limiting. The exemplary linkage assembly 128 may not include four links or may include more than four links. The shape, dimension, arrangement, or mounting of these links may vary as well in accordance with the present application. For example, the links may be strips, slabs, sticks, bars, rods, or any other suitable shapes. The links may be made of a sheet metal, formed from a plastic, or any other suitable material. One would appreciate that any suitable assembly coupling the flow controller 106 to the actuator 108 is within the scope of the present application.

Through the exemplary linkage assembly 128, the actuator 108 moves the flow controller 106 to different positions for varying the supply air volume to a space or a room in response to a thermal load. For example, to open the VAV diffuser 100 for discharging a larger volume of supply air, the actuator 108 rotates the threaded shaft 126 in one direction, resulting in the hub 130 moving upwardly along the shaft 126. Since the first link 132 of linkage assembly 128 is affixed to the hub 130, the first link 132 moves upwardly with the hub 130 and pulls the fourth link 138 up. In response to this upward movement, the fourth link 138 rotates and at the same time pulls the second link 134 and the third link 136 inwardly. As a result, the third link 136 rotates or pulls the flow controller 106 away from the diffuser housing 102 or in particular away from the side walls of the diffuser cone 112. In a case where the flow controller 106 is hinged on the supporting structure 104 or on an edge of the supporting structure 104, the flow controller 106 rotates around the hinge 120. Consequently, the VAV diffuser 100 is opened up and a larger volume of the supply air can be discharged into a space or a room. This opening operation is depicted in FIG. 1A.

Similarly, to close the VAV diffuser 100, the actuator 108 rotates the threaded shaft 126 in the opposite direction such that the hub 130 and the first link 132 move downwardly along the shaft 126. The first link 132 pulls the fourth link 138 down. In response to this downward movement, the fourth link 138 rotates and at the same time pushes the second link 134 and the third link 136 outwardly. As a result, the third link 136 rotates or pushes the flow controller 106 towards the diffuser housing 102 or in particular towards the side walls of the diffuser cone 112 to close the VAV diffuser 100. Similar to opening the VAV diffuser 100, the flow controller 106 rotates around the hinge 120 if the flow controller 106 is hinged on the supporting structure 104 or on an edge of the supporting structure 104. Consequently, none or little of the supply air will be discharged into a space or a room. This closing operation is depicted in FIG. 1C

In addition, through the exemplary linkage assembly 128, the actuator 108 can place the flow controller 106 in any intermediate position between the opened position and the closed position in response to a thermal load. Depending on the initial position of the flow controller 106, the actuator 108 may rotate the threaded shaft 126 in a direction towards the fully opened position or in an opposite direction towards the closed position until it reaches the desired volume of the supply air. The flow controller 106 in an intermediate position is illustrated in FIG. 1B.

In various embodiments, the exemplary VAV diffuser 100 may include a plurality of the linkage assembly 128, each of them corresponding to one vane or blade. For example, in a case where the flow controller 106 includes four blades, the exemplary VAV diffuser 100 may include four linkage assemblies 128. Each of the linkage assemblies 128 corresponds to one blade that is rotatably mounted on the supporting structure 104 and moves the respective blade to different positions for varying the supply air volumes. In such configurations, the supporting structure 104 may be formed with a plurality of linkage holes 118 for accommodating the respective first links 132.

Turning now to FIGS. 2A-2C, there is depicted an alternative exemplary VAV diffuser 200 in opened, intermediate and closed positions, respectively. Similar to the exemplary VAV diffuser 100, the exemplary VAV diffuser 200 generally includes the diffuser housing 102, a supporting structure 202, a flow controller 204 and the electric actuator 108. The supporting structure 202 may be affixed to the diffuser housing 102. The electric actuator 108 may be removably mounted on the supporting structure 202, and moves the flow controller 204 to vary the volume of supply air discharged through the discharging opening. Like the exemplary VAV diffuser 100, in various embodiments, the exemplary VAV diffuser 200 is configured such that the electric actuator 108 is accessible from the room side and removable from the diffuser housing 102 while the diffuser housing 102 is coupled to the supply air conduit, the supporting structure 202 is affixed to the diffuser housing 102 and the flow controller 204 remains within the diffuser housing 102.

Like the supporting structure 104, the supporting structure 202 may be circular, polygonal or of any other suitable shape, and may be affixed to the diffuser housing 102 in the same or similar manner. Unlike the supporting structure 104 formed with a shaft hole 116 and one or more linkage holes 118, the supporting structure 202 may be formed with a mounting hole 206, through which the electric actuator 108 may be screwed to supporting structure 202 and removed from the supporting structure 202 after unscrewing. Preferably, the supporting structure 202 and the mounting hole 206 are configured such that the electric actuator 108 is positioned substantially along the centerline or the central axis A of the diffuser housing 102 and the threaded shaft 126 extends substantially upwardly once the VAV diffuser 200 is mounted to a ceiling.

In various embodiments, the flow controller 204 is movably coupled with the electric actuator 108, or with the threaded shaft 126 of the electric actuator 108. The flow controller 204 may be a disk, having a circular, polygonal or any other suitable shape. In some cases, the flow controller 204 may be formed with a threaded hole, which threadedly couples the flow controller 204 with the threaded shaft 126 of the electric actuator 108. In other cases, the flow controller 204 may be formed with a through hole, through which the threaded shaft 126 of the electric actuator 108 extends. In such cases, a nut 140 may be used to couple the flow controller 204 with the threaded shaft 126 of the electric actuator 108. The nut 140 may be affixed on the flow controller 204 such as by welding, or monolithically or integrally formed with the flow controller 204. The flow controller 204 may be formed with a guide hole 208.

In various embodiments, the exemplary VAV diffuser 200 may further include a guide 210, one end of which is affixed on the supporting structure 202 for preventing the rotation of the flow controller 204. The sizes and shapes of the guide 210 may vary in accordance with the present application. For example, the guide 210 may be a rod with a circular or polygonal cross section. The guide 210 extends substantially upwardly through the guide hole 208 formed in the flow controller 204 and slidably couples with the flow controller 204. When the threaded shaft 126 rotates, the guide 210 prevents the flow controller 204 from rotating with threaded shaft 126. As a result, the flow controller 204 moves up or down along the threaded shaft 126.

To open the exemplary VAV diffuser 200, the actuator 108 rotates the threaded shaft 126 in a direction, which in turn drives the flow controller 204 down away from the diffuser neck 110 until it reaches the fully opened position, as shown in FIG. 2A. To close the exemplary VAV diffuser 200, the actuator 108 rotates the threaded shaft 126 in an opposite direction, which in turn drives the flow controller 204 up towards the diffuser neck 110 until it reaches the closed position, i.e. until it seals the diffuser neck 110, as shown in FIG. 2C. In response to the variation of the thermal loads, the flow controller 204 can be controlled and positioned in an intermediate position, as shown in FIG. 2B, between the fully opened position and the closed position to achieve the desired volume of the supply air.

The exemplary VAV diffusers 100, 200 may further include one or more sensors 144 to measure room air temperature, supply air temperature, supply air flow rate, or other parameters, and a control system to regulate the movement of the flow controller based on the measurement by the sensors 144. The sensors 144 and the control system can be mounted either inside or outside of the diffuser housing 102. For example, a supply air temperature sensor 144 may be mounted in the supply air conduit or in the diffuser neck 110 of the diffuser housing 102. A room air temperature sensor 144 may be mounted externally, such as on a wall of a room, and electrically coupled to the control system. The room air temperature sensor 144 may also be mounted within a room air flow path or a room air induction channel 212, as shown in FIGS. 2A-2C.

The room air induction channel 212 is configured to induce the flow of a certain amount of room air over the room air temperature sensor 144 to ensure accurate measurement of the room air temperature. The room air induction channel 212 may be arranged or constructed on the diffuser housing 102, on the supporting structure 104 or other suitable positions as long as it induces room air over the sensor 144. By way of illustration, FIGS. 2A-2C depicts a room air induction channel 212 that is formed on the supporting structure 104. In addition, the room air induction channel 212 can be included in any of the suitable VAV diffusers, such as the exemplary VAV diffuser 100 shown in FIG. 1A and the exemplary VAV diffuser 200 shown in FIG. 2A.

Configuration of the room air induction channel 212 can vary in accordance to the present application. By way of illustration, FIG. 2A depicts the room air induction channel 212 that includes one or more induction nozzles formed on the supporting structure 104. The one or more induction nozzles may be configured such that the supply air or primary air exits the nozzles at a direction substantially parallel to the supporting structure 104, hence effectively inducing room air or secondary air into the region or over various sensors if any. In addition, the one or more induction nozzles may form an angle with respect to each other.

Another example of the room air induction channel 212 is depicted in FIG. 2D. As shown, the room air induction channel 212 includes two C-channels 212 a and 212 b that face to each other. C-channel 212 a extends substantially from one side to another and has an opening at one end. C-channel 212 b is relatively short and is positioned proximity to the opening at the end of the C-channel 212 a. The induced air passes through the opening and flows over sensors if any.

As shown in the figures, the exemplary VAV diffusers 100, 200 may further include an appearance plate 142. The appearance plate 142 may be attached to the supporting structure 104 or to the diffuser housing 102. In various embodiments, one edge of the appearance plate 142 may be rotatably mounted on the supporting structure 104, such as by being hinged or hooked to a bracket or a plurality of brackets 302 that is affixed on the supporting structure 104. The other edge or the opposite edge of the appearance plate 142 may be detachably attached to the supporting structure 104, such as by a bracket, a hook, a loop or a ring 304 that is affixed on the supporting structure 104. The detachable attachment of the appearance plate 142 may use other mechanisms, for example by a magnet or snap fit.

In various embodiments, the exemplary VAV diffusers 100, 200 may further include an insulation layer 306 that is overlaid on the flow controller 106 and/or the supporting structure 104. Generally, the insulation layer 306 is overlaid on a side that faces the supply air conduit and is along the flow path of discharged supply air. It may cover the entire surface of the flow controller 106 and/or the entire surface of the supporting structure 104. It may also cover only a portion of the flow controller 106 and/or a portion of the supporting structure 104. The insulation layer 306 may include an absorption material that can absorb sound, vibration, or condensation. The insulation layer 306 may also include other materials that can eliminate or reduced other undesired effects. In some cases, the insulation layer 306 may include a foam sheet and/or other suitable insulation means.

Normally, the supply air for cooling commercial buildings is at about 55° F. or above. This is because a supply air at lower temperatures may produce condensation or precipitation that can deteriorate VAV diffusers. With an insulation layer 306 that can absorb condensation in place, the exemplary VAV diffusers 100, 200 may be used to achieve the same conditioning effect by discharging a small amount of supply air at lower temperatures. By doing so, the exemplary VAV diffusers 100, 200 may save energies because discharging a small amount of supply air requires less energy.

Referring now to FIGS. 4A-4C, there is depicted an operation for repairing or replacing an actuator in the exemplary VAV diffusers in accordance with the present application. This is an example showing the easy accessibility and effortless serviceability of the exemplary VAV diffusers. As shown, dismounting an actuator involves basically two steps: detaching one edge of the appearance plate 142 from the supporting structure 104 and dismounting or unscrewing the actuator 108. Replacing with a new actuator can be achieved by simply reversing these two steps. Whether dismounting or replacing the actuator, there is no need to dismount the exemplary VAV diffusers from the ceiling or from the supply air conduit. Moreover, there is no need to disconnect or disassemble other components from the exemplary VAV diffusers. As such, it saves time, reduces cost, and requires no special training.

For convenience in explanation and accurate definition in the appended claims, the terms “up” or “down”, “inwardly” or “outwardly”, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

What is claimed is:
 1. A variable-air-volume diffuser comprising: a diffuser housing formed for coupling to a supply air conduit and defining a discharging opening for discharge of supply air from the supply air conduit into a room; a supporting structure affixed to the diffuser housing; a flow controller for varying a volume of supply air discharged through the discharging opening; and an electric actuator mounted on the supporting structure for moving the flow controller to vary the volume of supply air; wherein the electric actuator is room-side accessible and removable from the diffuser housing while the diffuser housing is coupled to the supply air conduit, the supporting structure is affixed to the diffuser housing and the flow controller remains within the diffuser housing.
 2. The variable-air-volume diffuser of claim 1, wherein the flow controller is movably mounted on the supporting structure.
 3. The variable-air-volume diffuser of claim 1, wherein the flow controller is pivotally mounted on the supporting structure by a hinge.
 4. The variable-air-volume diffuser of claim 1, wherein the flow controller includes a plurality of blades and each blade is movably mounted on the supporting structure.
 5. The variable-air-volume diffuser of claim 1, wherein the flow controller includes four blades and each of the four blades is movably mounted on the supporting structure.
 6. The variable-air-volume diffuser of claim 1, wherein the electric actuator includes a stepper motor.
 7. The variable-air-volume diffuser of claim 1, wherein the electric actuator is removably mounted on a bracket that is affixed on the supporting structure.
 8. The variable-air-volume diffuser of claim 3, further comprising a linkage assembly that connects the flow controller to the electric actuator, wherein the linkage assembly is configured such that the electric actuator rotates the flow controller around the hinge.
 9. The variable-air-volume diffuser of claim 4, further comprising a plurality of linkage assemblies, each linkage assembly connecting a respective blade of the plurality of blades to the electric actuator.
 10. The variable-air-volume diffuser of claim 8, wherein the supporting structure is formed with a shaft hole and a linkage hole; the electric motor includes a threaded shaft that extends substantially upwardly through the shaft hole in the supporting structure; and the linkage assembly includes: a hub threadedly coupled to the threaded shaft of the electric actuator; a first link affixed to the hub at one end and extending downwardly through the linkage hole in the supporting structure; a second link rotatably mounted on the supporting structure at one end; a third link rotatably mounted on the flow controller at one end, and a fourth link, one end of the fourth link rotatably connected to the other end of the first link and the other end of the fourth link rotatably connected to the other ends of the second and third links.
 11. The variable-air-volume diffuser of claim 10, wherein the hub is operably coupled to the threaded shaft of the electric actuator.
 12. The variable-air-volume diffuser of claim 1, wherein the supporting structure is formed with a mounting hole for mounting and removing the electric actuator.
 13. The variable-air-volume diffuser of claim 1, further comprising a guide affixed to the supporting structure and extending substantially upwardly for preventing rotation of the flow controller.
 14. The variable-air-volume diffuser of claim 13, wherein the electric actuator includes a threaded shaft that extends substantially upwardly; and the flow controller is formed with a shaft hole and a guide hole, wherein the flow controller is threadedly coupled with the threaded shaft of the electric actuator through the shaft hole and is slidably coupled with the guide through the guide hole.
 15. The variable-air-volume diffuser of claim 1, wherein the flow controller is a disk.
 16. The variable-air-volume diffuser of claim 1, further comprising an appearance plate that is removably attached to the supporting structure.
 17. The variable-air-volume diffuser of claim 16, wherein one edge of the appearance plate is rotatably hinged to a bracket affixed on the supporting structure, and the opposite edge of the appearance plate is detachably secured to the supporting structure.
 18. The variable-air-volume diffuser of claim 1, further comprising an insulation layer that is overlaid at least on a portion of the flow controller.
 19. The variable-air-volume diffuser of claim 1, further comprising a sensor for measuring room temperature, temperature of the supply air, or flow rate of the supply air.
 20. The variable-air-volume diffuser of claim 1, wherein the diffuser housing comprises: a diffuser neck formed for coupling to the supply air conduit; and a diffuser cone formed for discharging the supply air in an angle with respect to a downward direction; wherein the diffuser neck and the diffuser cone are integrally formed or coupled to each other.
 21. A variable-air-volume diffuser comprising: a diffuser housing formed for coupling to a supply air conduit and defining a discharging opening for discharge of supply air from the supply air conduit into a room; a supporting structure affixed to the diffuser housing; a plurality of blades movably mounted on the supporting structure for varying a volume of supply air discharged through the discharging opening; and a linkage assembly connecting the plurality of blades to an electric actuator; wherein the electric actuator is accessible from room side and removable from the diffuser housing while the diffuser housing is coupled to the supply air conduit and the supporting structure is affixed to the diffuser housing and connected to the linkage assembly.
 22. A variable-air-volume diffuser comprising: a diffuser housing formed for coupling to a supply air conduit and defining a discharging opening for discharge of supply air from the supply air conduit into a room; a supporting structure affixed to the diffuser housing and formed with a mounting hole; a flow controller for varying a volume of supply air discharged through the discharging opening; a guide affixed to the supporting structure and extending substantially upwardly for preventing rotation of the flow controller; and an electric actuator mounted on the supporting structure through the mounting hole for moving the flow controller to vary the volume of supply air; wherein the electric actuator is room-side accessible and removable from the diffuser housing through the mounting hole of the supporting structure while the diffuser housing is coupled to the supply air conduit, the supporting structure is affixed to the diffuser housing and the flow controller remains within the diffuser housing. 